Electric switch



Nov. 15, 1927.

F. C. DAVIS ELECTRIC SWITCH Filed March 27, 1926 +2 m i 'ZI ILUI 1/, r 17 18 P 36-\ (Q 3 in 79; k741i] Y EAL K Q Inventor.

, electrically operated devices which may be Patented Nov. 15, 1927.

FRANCIS C. IPA'VIS F TORONTO, ONTARIO, CANADA.

ELECTRIC SWITCH.

Application flled llarch 27, 1926. Serial No. 97,978. I

The principal object of the invention is to devise a switch for controlling the circuits of.

actuated in a very simple manner and par-- ticularly toprovide a form of switch for use in the operation of electrically controlled elevators which will obviate the occurrence of accidents in the operation of elevators through failure to properly close the doors,

and which will ensure the properclosing of the door before the elevator can be started.

The principal featureof the invention consists in the novel construction and arrangement of parts, whereby a tilting circuit-closing member is actuated by gravity to close the circuit following the complete closing of the door.

In the drawings, Figure l is an elevational view showing the mechanism of my im-.

proved switch in the circuit closing position.

Figure 2 is a vertical sectional view through the line 22 of Figure 1.

Figure 3 is an elevational view from the rear side showing the switch member in the open position.

move.

In the operation of electrically "controlled elevators it is very important that the doors giving access to the elevator. car be completely closed before the car is permitted to Many very. serious and" fatal acc1- dents have occurred through failure on the part of the operator to properly close the door before starting his car.

In the construction of switch herein shown a casing 1 is provided in which a sliding bolt 2 is horizontally arrangedhaving the end 3 projecting therefrom to be engaged by the elevator 'door or a suitable extension therefrom.

Thebolt 2 is actuated to move outwardly by a weighted arm '4 pivotally mounted on a pin 5, rigidly secured in the casing.

The bolt 2 is formed with a pair of flanges 6 and 7 which form an annular groove 8 and it is also provided with a stop flange 9 which limits its outward movement.

A lever10 mounted upon a fixed .pivot pin 11 secured inthe back of the casing 1 is pro-g vided with a pin 12in its lower end which extends into the annular groove 8 and is engaged by the flanges 6 and 7.

The upper end of the lever with an open slot 13.

Pivotally mounted upon the pin 11 1s 1a plate 14 which has a pin 15 secured therein 10 is formed:

are t which extends into the open slot 13 and has considerable. freedom-of movement therein. Supported from the plate 14 is a block 16 of insulating material which carries the clips 17 at either end for supporting the tubular holder 18 for-the mercury contact tube 19.

The tubular holder 18 is provided with an opening 20 through which the contacts with- 1nthe glass tube 19 may be observed.

The tube 19 is provided with a terminal 21 arranged adjacent to one end and connected to the binding screw 22.

The other terminal 23 of the mercury tube is connected to a binding screw 24 and extends horizontally within the tube to a point close to the terminal 21. x

A quantity .of mercury is arranged within the tube from which air is exhausted and the arrangement of the terminals and the'quantity of mercury is such, that the connection between the terminals is not established by the mercury until the tube has moved past the horizontal with the terminal 21 at the lower end. a c 7 Suitable .wire connections 25 and Y26 are connected with the binding screws 22 and 24 .to lead to the control circuit.

In the operation of this device the weight of the pivotal arm 4 holds the bolt 2 in the outwardly projected position illustrated in Figure 3 when the elevator door is open. When the bolt is in this position, the lever 10 by reason of the contact of the pin 12 with the flange 6 of the bolt, is tilted so that the upper end is past the vertical centre line through the pivot pin 11 toward the side X- of the casing and the pin 15 is in engagement with the lowermostside of the slot. Theplate 14 and the mercury contact tube 19 us tilted at an angle so that the mercury contained within the tube is arranged at the end of the tube farthest from the terminal 21. v 9

Upon the closing. of the elevator, door the bolt 2 is pushed inwardly and the flange 7, engaging the pin 12, swings the lever 10 on its pivot. This movement continues until the pin 12 moves well-past the Vertical line vertical line through saidv pivot, but immediatel v the pin 15 doesfpass over the vertical; line of the pivot the mercury within the tube will flow to the opposite end and on account of the width of the open slot 13, the pin 15 the tipping of the plate 14 onits pivot, con- ,sequently if the operator has opened his control, the circuit will be established without an arc.-

In the reverse action of the switch herein described, when the door is open the weight of the arm 4 pushes the bolt 2 outwardly and thelever 10 swinging on its pivot tilts the plate 14: and immediately the pin 15' passes the vertical centre line it will tip suddenly because of the width of the slot 13.

It will be noted that because of the arrangement of the terminal 23 contact will he 'mainta ned between the terminals 21 and 23 while the tube 19 is tipping to the horizontal, because the terminal 23 is arranged horizontally in the tube but the moment the pin 15 passes the vertical line of its pivot point the mercury will flood to the other end and tip the tube with a sudden-movement.

A switch such as described is very positive in its action and'will wear indefinitely and as its operation is not dependent upon spring action of any kind it will operate with accuracy and dependability.

The switch has been herein described as particularly adapted to elevator controls but it must be understood that it may be very readily applied to other control circuits, it being merely necessary to provide suitable means for operating the bolt 3.

What I claim as my'invention 1s:

1. A safety switch, comprising a casing having a horizontal sliding bolt-therein, a fixed pivot arranged above said bolt, an arm ivoted intermediate of its length on said ed pivot and having its lower free end operatively engaging said bolt, said arm having its upper end forked, means engaging said sliding bolt to hold it in an outward position, a plate pivotally mounted on said fixed pivot and extending thereabove, a mercury contact tube arranged in a horizontal position on said plate and adapted to be moved bodily to either side of said fixed pivot to make and break an electrical connection, a pin carried by said plate and disposed in alignment with the forked upper end of said pivoted arm and adapted to be engaged thereby to effect the movement of said plate and tube carried thereby.

2. A safety switch, comprising a casing having a horizontal sliding bolt therein, a fixed horizontal pivot arranged above said sliding bolt, an arm pivoted intermediate of its length on said fixed pivot and having its lower free end operatively engaging the slid' ing bolt, said arm having its u per free end forked, means for holding said liolt outward, an insulating block rotatably mounted on said-fixed pivot and adapted to be rocked thereon, means on the up er side of said .block for receivingand ho ding a mercury contact tube, and a pin extending from said block above its pivot and engaging the forked end of said arm.

3. In a safety switch, a casing, a bolt slidably mounted in said casing having one end projecting outwardly beyond the casin means within the casing for urging said b0 t outwardly, spaced flanges on said bolt withinthe casing, a lever mounted intermediate of its length on a pivot fixed to said casing and having a pin secured to the lower free end extending between the flanges on said bolt and adapted to be engaged thereby in operative contact, a mercury tube mounted on said fixed pivot for rocking movement to either side thereof, and means carried by the mercury tube mounting adapted to engage the upper free end of said lever in loose operating contact.

FRANCIS o. DAVIS. 

